A waistband fastener of the type which comprises a latch rail fixed to one portion of the waistband and on which latch rail a slider or carriage connected to the other portion of the waistband is guided in an adjustable and latchable manner, in such a way that a latch finger engaging between the teeth of the latch rail is provided for the slider, is known from U.S. Pat. No. 4,180,891. There, a lever hinged to the slider effects the engagement of the latch finger. The hinged lever has two arms, one of which serves as an operating grip and the other of which continues or merges into the latch finger which directly engages with the latch gaps or recesses of the latch rail. Although in that construction the disposition of the hinge axis very close to the rail is achieved, relative movements between the latch rail and the slider result due to the pivoting motion of the hinged lever. Moreover, a rather high pressure application is required. For example, if the tooth gaps are not positioned, with regard to the latch finger, in such a way that the latter can be pivoted therein, the teeth can be damaged. Furthermore, the high space requirement for the swung-out position of the hinged lever is deemed to be a disadvantage, as well as the risk of an undesired opening due to accidental contacts with the hinged lever, which risk cannot be completely excluded. Additionally, the manufacture of such a waistband fastener is relatively expensive.